The present invention relates to a valve for placing onto a container, in particular onto a cylinder in which a pressure is built up, having a valve housing in which at least one valve seat is provided, the valve which is independent of the cylinder pressure being situated between a piston, which slides in a cylinder space and the valve housing, and the cylinder contents connected to the piston, and on the other side a force accumulator which can be changed in its force pressing on the piston.
In many situations in the private and industrial sector, pressure cylinders of steel or aluminum are used which are filled with gases for a certain requirement. In the cylinder, these gases are under a gas pressure of, for example, up to 300 bar.
As an example, reference is made to the use of these cylinders in the drinks industry. For many drinks, a CO2 cylinder is used for adding CO2 to the drink.
A further considerable use is found in the packaging of drinks, in the form of protection of the bottled drink until it is consumed. The addition of a compressed gas prevents the growth of microorganisms.
The same is also true for medical gases, for example for the additional supplying of a person with oxygen. In this case too, the oxygen is supplied in gas cylinders under very high pressure. However, the gas must be at a considerably lower pressure in the inhalation apparatus.
Since the gas in the cylinders, as mentioned above, is under a very high pressure, up to now expensive reducing systems with flow meters and manometers have been required for the removal of the gas.
For example, U.S. Pat. No. 5,520,214 A discloses a valve for supplying oxygen to a patient, in which a filling valve and a regulated extraction valve are situated in a valve body. In this case, a piston, which is supported against a helical spring, the pressure of which can be set, is mounted in a floating manner in a cylinder space. On the other side, the piston is connected fixedly to the ball of a ball valve. The oxygen which is to be discharged from the cylinder builds up in front of this ball valve.
U.S. Pat. No. 4,815,692 discloses a valve, in which a piston, which is connected fixedly to a valve cone, is arranged in a cylinder space in a manner such that it can move counter to the force of disk springs. In this case, the space on the other side of the disk springs can be placed under pressure, so that the valve cone lifts from its seat and opens up an outlet for a medium which is to be discharged.
A valve of the above-mentioned type is disclosed in DE 10 84 215 B. In this case, a piston which is supported against a changeable force of a helical spring is pressed via a spindle pin against a pin via which, in turn, a valve cone can be lifted from its valve seat. If the pressure of the medium flowing into a cylinder space is too high, the piston is pushed back against the adjustable spring and at the same time the opening width of the valve seat is reduced.
The present invention is based on the object of developing a pressure-reducing valve which is of extremely simple construction and can be operated very reliably even without specialist knowledge.